Set /persist/ssn and 60isn to permission 664

They were 666 which can be modified by users.

Bug: 9668280
Change-Id: I61a97d8c9ff91b73e705969569087bae75c3d237
Signed-off-by: Iliyan Malchev <malchev@google.com>
diff --git a/init.flo.rc b/init.flo.rc
index 92918f9..65d78f8 100644
--- a/init.flo.rc
+++ b/init.flo.rc
@@ -189,6 +189,9 @@
     # Modify from 777 (for lightsensor calibration data) to 664
     chmod 664 /persist/lightsensor/AL3010_Config.ini
 
+    chmod 664 /persist/ssn
+    chmod 664 /persist/60isn
+
     #Provide the access to hostapd.conf only to root and group
     chmod 0660 /data/hostapd/hostapd.conf